electrical/lighting for Serveta

[mosaicmama]

Hi folks - I thought I had my '74 Serveta barn find up and running but he's thrown me a new curve ball and I need some advice.

It was running fine but the taillight was a little loose - but I had running light, hi/low beams and speedo lights working.
Bike sat for about 3 weeks uncharged.
Tested battery before riding again, it was at 6.4 volts.
Rode for 15minutes and all lights were gone and batt drained to zero.
Recharged Battery
Ran bike - still no lights but battery drained FAST back to ZERO.

Any clue what readings I should be getting on my volt meter off the wires from the stator (2 yellow and 1 red)?
Any other suggestions?? It's a motoplat stator BTW and I just changed over the points and condensor and again the bike runs...

Thx,

Lynn

[ArmandTanzarian]

Motoplat electrics are notorious. If you haven't any deep objections to changing the setup I'd just get an electronic kit and a wiring loom.

[firekdp]

Firstly I would check that the battery is definately OK, just because it's voltage is +12v after charging doesn't mean that it is holding that charge. The motoplat system needs a good battery to work correctly.
To test the stator measure between each yellow and red in turn (and disconnected) at idle each should read around 5v rising, higher with revs.

[mosaicmama]

FYI this is a 6v/6pole stator bike. I bought the battery new a couple of weeks ago, rode it for about 1hr with all lights in working order, then it sat for a little over a week. Checked the battery before riding again, it was 6.4v so good to go. Rode again for 15 minutes and lost all lights and battery juice.

From red wire to ignition disconnected:

Y1 - Ground 5VAC idle, up to 12VAC rev
Y2 - Grnd 5vAC idle, up to 12vAC rev


So hooked the red wire to ignition back up, then disconnected all wires to rectifier to see if the battery would power anything and I get nothing but a quickly drained battery.